Energy Management in PV, Fuel Cell, and Battery Hybrid System Using MATLAB Simulink

Introduction

In modern renewable energy systems, hybrid architectures combining photovoltaic (PV) panels, fuel cells, and battery storage are increasingly popular for ensuring continuous power supply. This blog explores a MATLAB/Simulink-based model designed for managing energy from a PV-fuel cell-battery hybrid system, highlighting its components, control strategies, and operational logic.

System Overview

The modeled hybrid system integrates:

• PV Panels: Eight series-connected 250 W panels, totaling 2,000 W output.

• Battery Storage: 300 V rated battery for energy storage.

• Fuel Cell: 4 kW nominal (up to 7 kW max) proton-exchange membrane fuel cell (PEMFC).

• DC Bus: Centralized 400 V DC bus for energy aggregation and distribution.

• Inverter: Single-phase inverter with LC filter to supply AC loads.

PV System and MPPT Control

The PV array is connected to the DC bus via a boost converter, controlled by the Incremental Conductance MPPT algorithm. This algorithm:

• Measures PV voltage and current.

• Generates duty cycles dynamically to extract maximum power.

• Maintains PV voltage stability as irradiance varies.

Battery Energy Storage Management

A bidirectional DC-DC converter connects the battery to the DC bus:

• The system maintains the DC bus at 400 V using a voltage and current control method.

• A PI controller regulates battery charging and discharging:

  • Compares actual and reference voltages.

  • Generates current references for battery management.

• Battery enters charging mode when surplus PV or fuel cell power exists; it discharges when additional power is needed.

Fuel Cell Operation Strategy

The fuel cell serves as a backup power source:

• Operates only when:

  • PV output drops below 600 W.

  • Battery SoC falls below 30%.

• Connected via a boost converter managed by current control logic.

• Supports both AC and DC loads during insufficient solar and low battery conditions.

• Excess fuel cell power is used to charge the battery once load demands are met.

Inverter and AC Load Supply

A single-phase inverter supplies AC loads through an LC filter:

• Utilizes D-Q transformation-based control:

  • Converts measured AC load currents into D-Q components.

  • Compares actual vs. reference D-Q voltages.

  • PI controllers regulate output, generating modulating PWM signals.

• Ensures stable AC voltage and current delivery based on available power from PV, battery, and fuel cell.

Dynamic Load and Power Flow Management

The simulation tests the system under variable irradiance (1.0 to 0.3 per unit):

• PV output adjusts with sunlight intensity.

• Initially, PV power meets load and charges the battery.

• As sunlight weakens and battery SoC decreases:

  • Fuel cell activates, supplying DC and AC loads.

  • Surplus fuel cell power charges the battery.

• System effectively maintains:

  • DC bus at 400 V.

  • Stable AC load supply (around 1,000 W).

Conclusion

This MATLAB/Simulink model demonstrates efficient energy management for hybrid renewable systems, leveraging:

• MPPT for optimized solar power harvesting.

• Intelligent battery charge/discharge control.

• Conditional fuel cell activation for backup power.

• D-Q control for reliable AC power supply.

Such a system ensures continuous load support, even during fluctuating solar conditions, showcasing the robustness of hybrid energy architectures.